The present invention relates generally to a means for mixing a plurality of components of fluid material. Devices of this type are known in the mixing art as static mixers. Such mixers are generally obtained by providing a tortuous path for the fluid streams to be homogenized or blended through the use of stationary baffles or other flow diverting structures of differing form and spatial arrangement within a flow bounding conduit or passageway.
Several designs of static mixing devices are known and are set forth, for example, in U.S. Pat. Nos.: 3,051,452, Nobel et al; 3,182,965, Sluijters; 3,239,197, Tollar; 3,286,992, Armeniades et al; 3,297,305, Walden; 3,358,749, Chisholm et al; 3,404,869, Harder; 3,583,678, Harder; 3,652,061, Chisholm; German Pat. No. 358,018, Burckhardt; and French Pat. No. 735,033, all of which are herewith incorporated by reference. Static mixing devices are further discussed in the following publications:
Pattison, Chemical Engineering, (May 19, 1969) p.94 et seq.;
Brunemann, Maschinenmarkt, Wurzburg, 79 (1973) 10, pp. 182-84;
Schilo, Ostertag, Verfahrenstechnik, 6 (1969) 2, pp. 45-47;
Brunemann, John, Chemie-Ing.Techn., 43 (1971) 6, pp. 348-54;
Hartung, Hiby, Chemie-Ing. Techno., 44(1972) 18, pp. 1051-56;
Hartung, Hiby, Chemie-Ing.Techn., 47 (1975) 7, pp. 309.
Often the flow-deflecting structures of these mixing devices consist of complicated, not easily manufactured configurations requiring casting, molding or extensive machine work or the like for preparation such as, for instance, those disclosed in U.S. Pat. Nos. 3,239,197; 3,404,869, and 3,583,678. Others are prepared by deformation of tubes, such as by crimping, as disclosed in U.S. Pat. Nos. 3,358,749 and 3,394,924, which most often is suitable for mixers employing low pressure and relatively small diameters only. U.S. Pat. No. 3,286,992 discloses a mixing device consisting of a plurality of helically wound, sheet-like elements which are longitudinally arranged in a tube in alternating left- and right-handed curvature groups. According to pertinent literature, one of the disadvantages of this kind of design is the dependency of its efficiency on a relatively limited range of length-to-diameter ratios of its elements, thereby causing a relatively large minimum length of the mixing apparatus. It has also been found that this design produces a lack of uniformity of mixing over the entire crossection (hole-in-the-center effect) under certain conditions and that the curved shape of the elements in larger diameter sizes is quite difficult to economically manufacture. Other prior art devices employ a plurality of plates or vanes extending outwardly from a central point of the tube, said vanes being angularly disposed in the manner of propeller blades, by which fluid striking the vanes will have imparted to it a swirling movement, with successive swirling means arranged to reverse the swirling movement of the fluid, the latter being achieved by giving opposite slopes to each succeeding set of vanes. Such a device is, for instance, disclosed in U.S. Pat. No. 3,652,061. These devices, however, have the disadvantage of requiring either slotting of the tube for inserting and affixing the vanes to it or the addition of a rod-like structure for supporting the vanes within the conduit.